I found a reasonably priced Pre-Ban Colt this afternoon and need some help. It is an HBar Sporter Match, recent enough to have been built with all the features except the evil bayonet lug. The front pin is not the push-thru variety my Bushmasters have, but looks like it takes a flathead screwdriver, is this large pin or small pin?My goal would be to create a carbine using a 16" M4 type upper and collapsible stock--would this work? Thanks!

If the front pivot pin is the same size as the rear take down pin, then it is a small pin. If the front pivot is larger than the rear take down then it is a large pin. You can also measure it to make sure.
Small- .250"
Large- .312"